Viewfinder Eyepiece Question

First....Happy New Year to all.

When using the Bulb exposure or the remote shutter release, is it a good idea to cover the viewfinder eyepiece on a DSLR? In the pre-digital era, I remember reading that failure to do so will allow additional light to expose the film. Is this relevant with a DSLR?

My camera manual (Canon EOS 400D) does not mention this. And, as far as I know, an eyepiece cover isn't even available from Canon.

Thank you.

There are eyepiece covers available. I got one with my 50D and 1D series camera's have a 'shutter'-kind of curtain in front of the eyepiece.

I have never used it though, but haven't been playing around with long exposures a lot either.

No need to cover the eyepiece. The mirror is flipped up during an exposure and it totally blocks the light path from the viewfinder to the sensor.

What you probably heard about was when shooting from a tripod, if your face is not pressed to the camera at the time of metering then light can enter the viewfinder from the eyepiece and confuse the camera meter.

I have a 400D and one came with mine. It was on the Canon camera strap.

You don't need to cover the eyepiece for a Bulb exposure (and you didn't need to do it with film, either).

There is no way for light to pipe to the sensor through the eyepiece.

The meter is off on Bulb.

JeffreyG wrote in post #9301374
No need to cover the eyepiece. The mirror is flipped up during an exposure and it totally blocks the light path from the viewfinder to the sensor.

What you probably heard about was when shooting from a tripod, if your face is not pressed to the camera at the time of metering then light can enter the viewfinder from the eyepiece and confuse the camera meter.

RDKirk wrote in post #9301546
You don't need to cover the eyepiece for a Bulb exposure (and you didn't need to do it with film, either).

There is no way for light to pipe to the sensor through the eyepiece.

The meter is off on Bulb.

The quoted posts tell the honest truth.

JeffreyG wrote in post #9301374
What you probably heard about was when shooting from a tripod, if your face is not pressed to the camera at the time of metering then light can enter the viewfinder from the eyepiece and confuse the camera meter.

You are probably correct. That is likely what I had heard.

Thanks.

Saying that there is no light will hit the sensor through the viewfinder is incorrect. I just took this photo with my body cap on my 20D. The exposure was caused by light coming through the viewfinder.

Byte size: ZERO | Content warning: NOT AN IMAGE

DDCSD wrote in post #9302424
Saying that there is no light will hit the sensor through the viewfinder is incorrect. I just took this photo with my body cap on my 20D. The exposure was caused by light coming through the viewfinder.

I took a frame right before this one with the viewfinder covered and the frame was completely black.

Perhaps we forgot the mirror is partially silvered?

JeffreyG wrote in post #9302475
Perhaps we forgot the mirror is partially silvered?

I did pop my flash in the viewfinder to get this, so it isn't likely to affect a real-world exposure. It only would happen if the flash was popped at the very end of the exposure, when the mirror was dropping and shutter was closing. I didn't try it at the very beginning of the exposure. If I only popped it in the middle of the exposure, the frame would be completely blank.

JeffreyG wrote in post #9302475
Perhaps we forgot the mirror is partially silvered?

If you run a sensor clean cycle and look at the mirror box, you see that the sub-mirror under the main mirror snaps closed. That was light forced through the foamed edge at the front of the mirror--that's why the fog is at the bottom of the frame.

Okay, if you nuke the seals, you can get light to the sensor through the viewfinder. Back in the film days, you could nuke the back of the camera around the seals a few times and cause fog there as well.

Sheesh.

kitjv wrote in post #9301360
First....Happy New Year to all.

When using the Bulb exposure or the remote shutter release, is it a good idea to cover the viewfinder eyepiece on a DSLR? In the pre-digital era, I remember reading that failure to do so will allow additional light to expose the film. Is this relevant with a DSLR?

My camera manual (Canon EOS 400D) does not mention this. And, as far as I know, an eyepiece cover isn't even available from Canon.

Thank you.

Page 22 in the 400D manual shows that the eyepiece cover comes with your camera and is located on the strap.

Page 153 tells you why you should use it, and shows you how.

20droger wrote in post #9302670
Page 22 in the 400D manual shows that the eyepiece cover comes with your camera and is located on the strap.

Page 153 tells you why you should use it, and shows you how.

Well, I'll be damned!! I should have listened to my parents & stayed in school.

I (embarrassingly) thank you.

DDCSD wrote in post #9302424
Saying that there is no light will hit the sensor through the viewfinder is incorrect. I just took this photo with my body cap on my 20D. The exposure was caused by light coming through the viewfinder.

Yep, the mirror is half-silvered, as Jeffrey said.

And remember, the metering sensor is in the viewfinder. By my own tests with the camera on a tripod in bright sunlight, light through the viewfinder can cause as much as 1-1/3 stop underexposure, worst case.

-js

number six wrote in post #9302973
Yep, the mirror is half-silvered, as Jeffrey said.

And remember, the metering sensor is in the viewfinder. By my own tests with the camera on a tripod in bright sunlight, light through the viewfinder can cause as much as 1-1/3 stop underexposure, worst case.

-js

But the meter is off when the camera is set for Bulb exposures, which is what this thread is about.